The present invention relates to compositions and means for conditioning fabrics. More specifically, certain particulate, water-insoluble, meltable conditioning agents are applied to fabrics, conveniently from an aqueous medium. Thereafter the fabrics are heated in an automatic clothes dryer, whereupon the conditioning agent melts and imparts desirable softening and antistatic benefits. The conditioning agents herein are especially designed for use in the aqueous alkaline media characteristic of pre-soak and laundering liquors and can also be used in aqueous rinse baths.
Fabric "softness" is an expression well defined in the art and is usually understood to be that quality of the treated fabric whereby the handle or texture is smooth, pliable and fluffy to the touch. Moreover, optimally softened fabrics are characterized by a desirable antistatic effect, which is exhibited by a lack of static cling.
It has long been known that various chemical compounds possess the ability to soften and impart antistatic benefits to fabrics. However, the effectiveness of any given compound may depend on its mode of use. For example, rinse-added fabric softeners, especially the quaternary ammonium compounds used in the detergent-free deep rinse cycle of a home laundering operation, provide exceptional conditioning benefits. Unfortunately, the cationic nature of these softeners causes them to interact undesirably with the common anionic surfactants such as the alkyl benzene sulfonates and is generally believed to preclude their use during the deterging cycle of a laundering operation involving commercial anionic detergents.
There has been a continuing search for fabric conditioning agents which are compatible with anionic surfactants and which can be used without regard to the presence or absence of such materials. Much of this work has involved the selection or blending of specific types of cationic conditioners. A few attempts have been made to provide nonionic softeners which, being free from cationic groups, do not interact with anionic surfactants.
Application Ser. No. 520,186, Haug et al., filed Nov. 1, 1974 (now abandoned), discloses detergent compositions containing particles consisting of fatty sorbitan esters having a melting point of from about 38.degree. C. to about 100.degree. C. and mixtures of said sorbitan esters with fatty quaternary ammonium salts. The particles adhere to fabrics washed in the detergent composition and melt to form a fabric conditioning coating on the fabrics when they are subsequently heated in a dryer.
It has been found that the compositions of Ser. No. 520,186 provide excellent fabric conditioning performance; however, in the early part of the drying cycle in a heated dryer, before melting of the particles occurs, some of the particles become separated from the fabrics due to the tumbling action of the dryer and these particles are carried by the moving air stream of the dryer into the dryer exhaust system where they can cause a clogging problem on the lint screen.
Application Ser. No. 624,032, Schilling, filed Oct. 20, 1975, and now abandoned, discloses detergent compositions containing particles prepared from a mixture of fatty sorbitan ester, a quaternary ammonium softener and polyethylene glycol. These particles diminish the lint screen clogging problem encountered with the particles described in Ser. No. 520,186.
It is the primary object of the present invention to provide fabric conditioning particles for use in detergent compositions, which particles exhibit high adhesion to fabrics in the dryer and thereby minimize the problem of softener loss through the dryer exhaust system and clogging of lint screens and also provide improved fabric softening and antistatic benefits compared to previously known particles used for this purpose.